The invention relates generally to apparatus and methods for the intravenous infusion of medication and, more particularly, to the automatic administration of intermittent medications in accordance with a predetermined medical therapy. A multichamber fluid bag is manufactured with a particular chamber size and geometry for implementing a prescribed infusion therapy. Because the infusion therapy is implemented by the bag""s chamber configuration, the administration of a complex medical infusion therapy is simplified.
It is now common for intravenous medications such as antibiotics, antivirals, antiemetics, chemotherapy and biotechnology drugs to be administered intermittently with a frequency as often as multiple times per day. Depending on the frequency of administration, the patient is either repeatedly connected to and disconnected from an intravenous (I.V.) line or is continuously connected to an I.V. line between administrations. In either case, the intermittent medications are generally administered by trained personnel using predefined procedures that often include a series of manual steps and a large number of disposable supplies. Each manual step in these procedures increases the risks associated with multiple manipulations and entry of I.V. sites.
The predefined procedures attempt to ensure the proper administration and the proper dosing of medication, while preventing incompatibilities between different drugs and preventing I.V. lines from clotting off between doses. Unfortunately, because of the manual steps included in these procedures, they have not been entirely successful in guaranteeing that medications are administered in the correct sequence, at the correct infusion rates, and in the correct volumes. Further, if the appropriate procedural steps are not performed within the required time frames, clots may form in the I.V. lines. Also, the manual steps included in these administration procedures are the principle source of infection and other complications that may arise during intermittent infusion therapy. Such problems and complications result in a longer hospital stay for the affected patient. Recent trends which have the patient trained to administer their own medications at home only exacerbate the problems and risks associated with intermittent infusion therapy. Further, elaborate or complicated infusion procedures are more likely to give rise to patient non-compliance by an untrained and less sophisticated home infusion patient.
One prevalent example of home health care therapy is the delivery of antibiotics and other medications utilizing the SASH protocol. SASH is an acronym that stands for Saline-Antibiotic-Saline-Heparin. The patient is trained to follow the SASH protocol by first attaching a saline filled syringe to the catheter to flush and clear the line. The patient then attaches a second syringe filled with the desired medicine or the patient attaches an IV set connected to a minibag, or other container, to the catheter and the medicine is delivered to the patient. A third syringe filled with saline is then attached to the catheter and the saline is injected to clear the line of all medication. Finally, a last syringe is attached to the catheter line and a heparinized solution is injected into the line to keep the line open and maintain the patency of the line for the next time a medication needs to be delivered.
The SASH system is currently delivered to the patient in two ways. In the first way the patient is given syringes, needles and vials of saline, medication, and heparin and the patient is instructed how to use the tools. In the second way, pre-filled syringes are supplied to the patient and instruction is provided.
The normal SASH procedure is to clear the line with a small injection of saline, administer the desired medication, clear the line again with another small injection of saline and then to inject heparin in the line to maintain patency of the IV site. The final injection of heparin into the IV site prevents coagulation in the line until the next administration of medication. Each of the fluids in the sequence is injected with a separate syringe with the only possible exception being the medication which may be delivered through an IV set.
Some medications require a relatively long period of time to inject because they will cause vein irritation or other complications if they are injected too quickly. To avoid this, the medication is diluted into a volume of solution, typically normal saline or DSW, up to 250 cc""s. The infusion time can take in excess of 60 minutes.
The above procedures involve the use of multiple syringes and needles, vials of saline and heparin and an IV drip set for medications that must be administered over a relatively long period of time. In this instance, the patient is connected to an IV drip after the initial line clearing injection of saline. When the IV drip is finished, the line is again cleared with saline from a syringe and the heparin is injected to maintain the patency of the line. The patient, nurse or pharmacist must fill the syringes from the vials for each of the injections and the needles used in the procedure must then be disposed of in a safe manner.
In addition to the sequential delivery of medications described above as the SASH process, patients frequently receive multiple medications. In some situations, these medications cannot be premixed until just prior to delivery to the patient.
Therefore it would be of great advantage to have a delivery system for multiple medications that does not involve the use of multiple syringes and needles. It would also be an advantage to have a medication delivery system that could be pre-filled with the correct volume of medication or multiple separate medications and which could be administered by the patient automatically in the correct sequence and/or concurrently over the desired time period. A desirable medication delivery system would be extremely simple to use, low in cost and could then be discarded without the usual concerns over the disposal of medical waste.
Accordingly, there exists a definite need for apparatus, devices and related methods for simplifying the administration of intermittent medical infusion therapy. The present invention satisfies these needs.
The present invention is embodied in a fluid delivery apparatus for the automated sequential or concurrent infusion of a plurality of pharmacological agents. The apparatus includes a plurality of chambers each configured with a respective geometry. Each chamber configuration controls the regimen with which said pharmacological agents are administered by controlling, e.g., the volume and the rate at which each pharmacological agent is administered.
The present invention provides an automated system for administering a variety of known drug regimens, thus eliminating the problems associated with the manual infusion system. Because the system uses an intravenous bag having multiple chambers with particular configurations, the contents of the bag can only be administered in accordance with the prescribed manner.
The fluid delivery apparatus may further include a common passageway and a plurality of chamber passageways. Each chamber passageway is coupled between the common passageway and a respective chamber. The fluid delivery apparatus may also include a high pressure clip having at least first and second positions, wherein, in the first position, the clip closes the plurality of chamber passageways and, in the second position, the clip permits fluid flow through the plurality of chamber passageways. The apparatus may also include a pressure sensing dome in fluid communication with the common passageway. Further, a frangible rupture seal may be situated between at least one chamber and the corresponding chamber passageway. Also, at least one chamber includes a sealable fill port and a sealable vent port.
The fluid delivery apparatus may further include an infusion pump with a spring driven roller for sequentially compressing the plurality of chambers. The pump may include a hinged door having a release tab. Alternatively, infusion pump may be actuated by an electrically driven motor for applying pressure to the chambers. The infusion pump may further include a display having status indicator lights, dose buttons, control buttons, a keypad, and a clock for controlling and indicating the status of administration of an agent.
Alternatively, the infusion pump may have one or more inflatable bladders for applying pressure to the chambers. Further, a flexible bladder pad may be coupled to a series of bladders for transferring pressure from the series of bladders to the chambers and locally distributing the force applied by any one of the series of bladders.
In an alternative embodiment, the invention is embodied in a fluid bag that is to be filled with pharmacological fluids associated with a desired medical infusion therapy for treatment of a patient. The bag has a plurality of chambers (which typically lie substantially in a plane) for containing the pharmacological fluids. Each chamber is sized and configured to implement the desired medical therapy when the fluids are automatically infused into the patient. The bag may be a unitary bag forming a cartridge.
In yet another embodiment, the invention is embodied in an automated fluid delivery apparatus for sequentially or concurrently infusing medications. The apparatus includes a fluid bag which is constructed from medical grade plastic sheets that are bonded together in a manner to define a plurality of separate chambers. The chambers lie in a plane and are configured with a respective geometry, position, and sequence for controlling the rate, volume and time of medication administration.
The invention is also embodied in a preassembled and easy to use cartridge for in-home patient use that will minimize patient mistakes and the amount of time needed for training the patient. The cartridge can be inserted in a rate controlled pump that will allow the slow administration of single or multiple medicines such as antibiotics or other drugs that can only be combined upon infusion.
The cartridge is contructed of two pieces that have been sealed together to form liquid containing chambers. Each chamber has a port for filling the respective chambers with the desired type and volume of fluid. For the SASH procedure, for example, the chambers would normally be filled in order with Saline, Antibiotic, Saline and then Heparin. At the exit port for each chamber is a one way check valve to prevent backflow into the chamber. Each chamber empties into a common dispensing line. A clamp can be used to close the dispensing line. A standard medical connector, such as a luer lock, heparin lock or needle is used to connect the cartridge to the patient""s IV set or catheter.
Different geometric configurations of the chambers can be used for controlling and varying the rate of flow. The geometry of the chamber can also be configured for a constant flow and to minimize the retention of residual fluid in the chamber.
In one aspect of the invention, a cartridge, with 4 chambers, is placed in a rectangular hopper. The cartridge is fed through rollers and fluid is squeezed out of the cartridge through an injection line. The rollers are driven by a motor which drives a shaft that drives the rollers. A clutch is used to limit the maximum amount of force that can be applied to the rollers.
In an alternative embodiment of the invention, there is only one roller that is held and guided by slots to roll over the cartridge. The roller is biased by a spring to roll over the cartridge and inject the fluids in the desired sequence. This embodiment can also use a motor and worm gear to drive the roller over the cartridge to dispense the fluid in the cartridge.
The features of the present invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawings.